Turbine control devices such as fuel control valves and variable vane actuators include numerous components that are subject to wearout failure modes over time. For example, various seals, bearings, gears, leadscrews and other components can cumulatively sustain small, yet significant, wear damage which is proportional to usage of the device, as well as process and ambient conditions. Unforeseen wearout of such components can be highly disruptive. For example, seal wearout, a common field problem seen on turbine fuel control valves, commonly leads to valve leakage, and ultimately costly unplanned outages. Additionally, wearout of the gear train or leadscrew may prevent a valve from properly opening or closing on demand, which could result in unsafe operation. Thus, the ability to detect wearout and to predict the amount of life left in various control device components (e.g., valve seals) is desirable.